1. Field of the Invention
The present invention relates to a device for regulating temperature in a room with the aid of an air flow, at a given temperature, pulsed therein.
2. Description of the Prior Art
It is known that, in air-conditioning installations, in order to ensure a maximum of comfort for the user moving in the air-conditioned room, on the one hand, the difference in temperature between the pulsed air and the ambient temperature of the room, as well as the velocity of the air pulsed therein, must be as small as possible and, on the other hand, the functioning of the device must be particularly silent. This latter condition implies that the air in movement, in contact with the wall of the conduits, moves at low velocity.
Now, to transport, at low velocity, a mass of air of which the temperature is close to that of the room to be air-conditioned and nonetheless presenting the quantity of calories, or negative kilogram calories, necessary to maintain the desired temperature in the room, the air-conditioning installations must convey large quantities of air and consequently be provided with supply conduits of large section, which increases in a prohibitive manner both their dimensions and their cost price. For these reasons, a compromise has therefore been made between, on the one hand, the conditions of optimum comfort for the user and, on the other hand, the dimensions and cost price of the conduits, by reducing the section of the latter with respect to their ideal dimensions, and by increasing the velocity of the air blown in the rooms to be air-conditioned. This results in a certain number of drawbacks.
A first drawback comes from the noise produced by the installation. In fact, it is known that the noise produced by an air-conditioning installation depends, on the one hand, on the noise produced by the air streams in movement over the walls of the ventilation conduits, noise which is directly connected with the velocity of the fluid in contact with this wall and, on the other hand, on that produced by the blowing into the room, which depends on the velocity of the air arriving therein.
A second drawback comes from the fact that, in winter, the pulsed air which is hotter than the ambient air, is directed towards the ceiling and, in summer, the pulsed air which is colder than the ambient air, is directed towards the floor of the room. Now, such a phenomenon is all the more important as the difference between the temperature of the pulsed air and that of the room is large. This difference in temperature in the systems according to the prior art being relatively great, this therefore results, both in summer and winter, in a permanent movement of the air inside the room which, added to the inherent velocity of blowing of this air, is such as to cause, by the current of air that it forms, a hindrance for the user. In order to avoid the air pulsed by the delivery vents being directed too easily, in winter towards the ceiling, and in summer towards the floor, said vents have been provided with fins directing the air blown in a direction opposite that which it tends to take normally. Although such an arrangement is such as to reduce the heat losses suffered by the air of the room in contact with the floor and the ceiling thereof, it nonetheless contributes, by creating eddies, to further increasing the noise and the current of air inside this room. Furthermore, this arrangement necessitates a reversal of the direction of the fins, at least twice a year, namely at the moment of passage from the position of heating to that of cooling, and vice versa, which increases the maintenance necessary for good functioning thereof.
Furthermore, it should be specified that the temperature gradient existing between the floor and the ceiling of the room, which is all the greater as the difference in temperature between the blown-in air and the ambient air is great, is also such as to cause a hindrance for the user.
It is also known that, in a room, part of the pulsed air flow is evacuated towards the outside, for example by a so-called VMC aeration device and/or by air leaks existing between the room and the outside. Now, this evacuated air is not evacuated with a sufficient flowrate to ensure maintenance of the room at a pressure close to atmospheric pressure and, if the room is not to be in a state of excess pressure with respect to the atmosphere, it is necessary to provide means for extracting this air. Now, as the latter contains a large number of calories, or negative calories, which, from the standpoint of the thermal balance, are important to recover, the extraction means are generally connected to the air plant where this air is processed and from which it is then returned into the rooms to be conditioned, via delivery conduits. Now, this modus operandi presents several drawbacks.
On the one hand, it requires the use of suction means such as fans, as well as additional conduits, which increases the noise, complexity, dimensions and cost of the whole of the installation.
On the other hand, the air extracted from each of the rooms is returned, after passage through the plant, in all the other rooms which, from the hygienic or microbial standpoint, particularly when this type of installation is employed in hospitals, hotels or offices, presents considerable risks for the health of the occupants of the rooms in question.
Moreover, in the existing installations, a principal conduit connected to the plant supplies a series of delivery vents disposed in parallel along this principal pipe. Now, depending on the length of the conduit existing between the upstream and downstream end vents, the pressure drop therebetween may be considerable, and the flowrates of air blown into the corresponding rooms may be very different.
One is thus led to increase the pressure of the air in the principal conduit so that the downstream delivery vents receive a sufficient pressure, which is translated by the existence of an excess pressure at the level of the upstream delivery vents. It is therefore necessary to reduce in the latter the pressure of delivery of the air, so that the velocity of the latter leaving these vents is not too high in order to cause neither noise nor disturbances for the occupants of the rooms in question. Apart from the loss of energy corresponding to the excess pressure to be applied to the pipe, this device presents the drawback of generating vibrations and whistlings at the level of the means for reducing the pressure upstream of the delivery vent.
U.S. Pat. No. 2,579,507 also proposes to pulse into a room air coming from a burner, with the aid of a convergent nozzle presenting a delivery opening and a extraction opening communicating with the room. However, apart from the fact that the temperature of the air blown in by this device is very much above the temperatures admissible in the domain of air-conditioning, the air admission opening is located upstream of the outlet orifice of the convergent nozzle and, under these conditions, the velocity of the air leaving the latter must be high in order to create a depression adapted to effect extraction of a sufficient volume of ambient air, this high velocity being translated by a high velocity of the air blown into the room, which, as set forth hereinabove, is such as to cause a hindrance for the users as well as a loud operational noise, which prohibits use thereof for applications such as for example air-conditioning in hospitals or other premises in which a certain degree of comfort is indispensable.